Addition-tester.



PATENTED JULY 2, 1907.

H. E. BROWN. ADDITION TESTER.

APPLICATION FILED AUG. 14, 1906.

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UNITED HUGH E. BROWN, OF BROWNS STATION, MISSOURI.

ADDITION-TESTER.

Specification of Letters Patent.

' Patented July 2,1907.

Application filed August 14, 1905. Serial No. 274,176.

To all whom it may concern:

Be it known that I, HUGH E. BROWN, a citizen of the United States, and aresident of Browns Station, Boone county, Missouri, have inventedcertain new and useful Improvements in r-\ddition-Testers, of; which thefollowing is a specification containing a full, clear, and exactdescription, reference being had to the accompanying drawings, forming apart hereof.

My invention relates to an addition tester, and is an improvement on theaddition tester patented by me February 3, 1903, No. 719,734, and theobject of my invention is to provide a much simpler and cheaper devicetor testing the correctness of addition than the device shown in mypatent above referred to.

My invention consists in certain novel features of construction andarrangement of parts which will be hereinafter more fully set forth,pointed out in my claims, and illustrated in the accompanying drawings,in which Figure 1. is a face view of an addition tester constructed inaccordance with my invention; Fig. 2 is a longitudinal section taken onthe line 2 2 of Fig. 1;

Referring by numerals to the accompanying drawingscd indicates a plate,preferably rectangular, upon which is rotatably arranged a star wheel,2, which is preferably provided with six arms, or fingers, although saidwheel may be provided with fingers, or teeth, the number of which isthree, or a multiple of three. As stated, I have shown this wheel, 2,with six arms, or fingers, and two of said arms, or fingers, which areoppositely arranged are marked with indicating characters O. Anotheroppositely arranged pair with the numbers l1, and the remainingoppositely arranged pair with the numbers 2 2. Upon the upper left handcorner of the plate, 1, appears the numbers, 1, 4, and 7 and upon theupper right hand corner of the plate appears the numbers 2, 5, and 8.

Pivotally mounted upon the face of the plate, 1, is a pawl, 3, the freeend of which is rounded, as indicated by 4, and is of such a size asthat it readily engages be tween the arms of the wheel, 2. A retractilecoil spring, 5, is secured at one end to this pawl, 3, and at itsopposite end to the left hand side of the plate, 1; and said spring isof such strength as that it retains the rounded end of the pawl betweenthe arms of the wheel, yet allows said wheel to be readily turned ineither direction. 7

Formed in the face of the plate, 1, below the pawl, 3, is a groove, (5,which is arranged in the form of an equilateral triangle, the apexthereof being marked with the letter A, the lower left hand corner withthe letter B, and the lower right hand corner with the letter It is awell known fact that any number, or the sum of any series of numbers,when divided by threes will leave as a remainder either naught, one, ortwo. In

the multiple of three test of addition, the throes and multiples ofthree are cast out of the sum of the digits of the numbers added bycasting the threes out of the first digit, adding the resultingremainder to a second digit, casting the threes out of the resultingsum, adding the resulting remainder to the next digit, casting out thethrees, and so on. The resulting last remainder is called the finalremainder, or check-figure. For example, in testing the addition of 85and 42, the sum of which is 127; the 3s cast out the first digit, 8,leaves a remainder of 2. Adding this remainder to the next digit, 5, andcasting the 3s out of their sum, 7, leaves a second remainder, 1. Addingthis second remainderto the next digit, 4, and casting the 3s out oftheir sum 5, leaves the third remainder 2. Adding this third remainderto the next digit 2 and casting the .is out of their sum 4 leaves thefourth remainder 1., which is the final remaiinler, or check figure. Nowthe threes and multiples of three are cast out of the digits of the sum,and the remainder is the second checktigure. 1f the two check-figuresare the same, no error unless an error or errors of three or a multipleof three has been made in the addition; but if the two checkfigures aredifferent, then this indicates that an error has been made.

The following methods may be employed in the use of my improved additiontester: To cast out the threes, the arms of the wheel, 2, bearing the 0sare arranged so that'they are parallel with the sides of the plate;then, said wheel is moved one notch to the left for each 1, 4, and 7;and one notch to the right for each 2, 5, and 8, making no movement fora O, 3, 6, or 9. When the figures of the addition that is being testedhave all been gone over, or indicated, by movements of the wheel, thecheck-figure will be upon the arms of said wheel that are parallel withthe sides. For example, to find the check-figure of 1.25. Having the Osof the indicator parallel with the sides of the plate, 1, the wheel ismoved one notch to the left for the 1, one notch to the right for 2, andone notch further to the right for the 5. Then, the 2 on the arms of thewheel that are parallel with the sides of the plate is the cheek-figureof 125, when the threes are cast out.

To test addition, (1st method,) find the check-figure of the numbersthat are added, and then the checkfigure of the sum of the figures thatare added; and these check-figures agree, if the addition is correct.

To test addition, (2nd method,) find the cheek-figure of the numbersadded, and if it be a zero, proceed with movements for figures in thesum. For 1, move the wheel one notch to the left before proceeding. For2, move the wheel one notch to the right before proceeding Then, whenmovements have been made for the figures of the sum, the arms, indicatedby 0, of the wheel will be parallel with the sides of the plate, if theaddition is correct.

(3rd inethoch) Proceed the same as in finding the checl-figure for thenumbers added. Reverse the direction of the movement for the figures inthe sum, and, if the addition is correct, the arms of the wheel, whichare indicated by 0, will be parallel with the sides of the plates: Forexample, in adding 25 and 10, the sum of which is 35, the wheel is movedone notch to the right for 2, one more notch to the right ior 5, onenotch to the left for 1 no movement for the 0, or the 3, and, as theremaining 5 is in the sum, move the wheel one notch to the left for said5. The adding being correct, the arms of the wheel bearing thecharacters 0, are parallel with the sides of the plate.

None of these methods detect an error of three, or a multiple of three.

In testing addition by means of the triangular groove formed in the faceof the plate, 1, a pencil point is placed in the apex of the triangulargroove, at A, and [or the figures in the numbers that are added, movethe pencil point as follows: one space from A to B, from B to O, andfrom O to A, for every 1, i, and 7; and one space in the oppositedirection for every 2, 5, or S. For figures in the sum, move the pointone space in the direction A to O, C to B, and B to A, ior every 1, i,or 7; and one space in the opposite direction for every 2, 5, or S. Nomovement is made for a 0, 3, 6, or 9. When movements have thus been madefor every 1, 4, 7,2, 5, and 8, the pencil point will, if the addition becorrect, be at A, the starting point. For example: when adding 28 and1.5, the sum of which is 43, move the pencil point from A to C for 2,from G to B for S, from B to O for 1, from G to B for 5, and from B to Afor 4. This leaves the pencil point at A, showing that the addition iscorrect.

An addition may also be tested, and the threes cast out by means ofmoving a pointer, or pencil, along a zigzag line, the points of theangles oi which are suitably numbered, or by using a triangle, or otherplane figure, the sides or divisions of which number three, or amultiple of three, and the angles or divisions oi which are suitablynumbered, or indicated.

Any of the above mentioned figures with lines, sides, or divisions sogrooved as to guide the pencil, or pointer, may be stamped or cut on thelace of the plate, 1., and used independently of, or in connection with,the Wheel, for testing addition, and [or fundamental, arithmeticaloperations. For example: in testing ad dition by using both the wheeland triangle:iind the check-figure of numbers added by using the wheel,and then find the check-ligure ol' the sum by using the triangle, and,if the addition is correct, the check-figures will agree.

I do not wish to confine myself to any particular form of pawl, or anyparticular shape of wheel, it only being necessary to provide a wheelhaving teeth to the number oi three, or a multiple thereoi.

An addition tester oi my improved construction is simple, inexpensive,easily operated, and is of great assistance to clerks, book-keepers, andmathematicians.

I claim:

In :1 device of the class described, a plate, a toothed Wheel arrangedfor rotation thereon. the teeth of which wheel are rounded at theirouter ends and provided with indicating characters, a spring actuatedpaw], having a rounded point engaging between the teeth of the wheel.and there being indicating characters arranged on the plate on oppositesides oi the wheel substantially as specified.

In testimony whereof. I have signed my name to this specification, inpresence of two subscribing Witnesses.

Witnesses W. A. Binmi'r.

S. Hum.

